I've trying to typeset a book which is duplex - with different running headers on left and right pages. Margin notes must always be on the left side of the page. However marginpar is not the easiest command to use.
The following is a one page example. Why don't the margin notes appear?
Marginal notes are mostly to appear in the outer margin. Trying to typeset notes in the left margin only works on a left (even) page. The first page is always a right (odd) page. Thus the optional argument has no effect. This optional argument can be used in the case it is not sure whether the marginal note will appear on an odd or an even page.
For enhancements to marginal notes you should take a look at marginnote. Page dimensions should be set with the geometry package.